Originally Posted by
CliffordK
[MENTION=381793]gugie[/MENTION] has successfully silver soldered a chrome crown without damaging the chrome. Lots of flux.
Thus, grinding/filing off the old cable guide to avoid excess heating, especially if it was originally brazed with brass, then using a low temp silver solder to re-affix.
I wouldn't braze onto chrome. I wouldn't trust the adhesion of the chrome to the underlying layer. It wouldn't look very good at any rate, and you'd repaint over it. I often remove top mount chain stay cable guides and braze a new one the bottom. I do this so I can route the derailleur cables under the BB. It's just cleaner looking to me that way. The upper ones get ground, filed and sanded clean, the bottoms get the chrome sanded off. Chrome dust ain't so great for you, so I wear a
HEPA filter mask for that operation.
My procedure to protect the chrome from heat, and me from the chrome:
1. Lots of flux, enough to create a barrier.
after
2. Use a proper respirator.
3. Use good ventilation
I work in the semiconductor industry for my day job. Some of the gases we use are deadly. I deal with high current, high voltage systems. Understanding the dangers and how to minimize risks is the very first job at work. I didn't do the above job without doing my homework.